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In order to study the effect of water propolis extract (WEP) on Dicentrarchus labrax under low temperature stress, sea bass juveniles were randomly divided into three groups: a control group fed with basal diet and two treatment groups fed with basal diet supplemented with 1.25 and 2.5 g kg-1 of water propolis extract. At the end of a ten week feeding trial sea bass were exposed to low temperature stress at 12°C for 24 hours. The growth performance, RNA/DNA ratio and changes in serum biochemical parameters were investigated. Dietary intake of propolis stimulated the specific growth rate (SGR), feed conversion efficiency (FCE), RNA/DNA ratio and ALP enzyme activity, while decreasing plasma triglycerides and AST activity. Supplement of 2.5 g kg-1 WEP in diet significantly increased the mean SGR and FCE up to 9% and 13.4% respectively in comparison to the control group. Low temperature stress elevated serum triglycerides, glucose and cortisol levels in all groups, however glucose and cortisol reached significantly lower end values in group receiving highest amount of propolis in diet. The present study suggests that ingestion of basal diet supplemented with 2.5 g kg-1 of propolis extract could prevent adverse effects of low temperature stress and promote the growth of sea bass.